Metadata cache management

ABSTRACT

In an embodiment managing a cache includes determining from metadata of a received service request whether a cache data response may satisfy the request as a function of recognizing a cacheable method name specification within request metadata by a service provider associated with the request, the embodiment further including determining whether the request is an inquiry or a request as a function of comparing an update frequency specification in the request metadata to a value of a time parameter associated with the cacheable method name in the metadata if the request may be satisfied by the cached data. The embodiment also includes searching the cache for the data response if determined the data is cacheable and the request is an inquiry, and sending the request on to a service provider if the data response is not a cacheable response or the request is an update request.

BACKGROUND

The present invention relates to cache management, and more particularlyto determining whether a response to a data request may be retrievedfrom a cache or retrieved from another resource. Serving a data requestfrom a cache instead of from an other resource can provide improvedcomputer system efficiencies. For example, a central processing unit(CPU) cache is a cache used by the CPU of a computer to reduce theaverage time to access data from memory, wherein the CPU cache is asmaller, faster memory having a lower retrieval latency than a mainmemory of the computer, and wherein it is desirable to manage the CPU tocache copies of data frequently used rather than use slower main memorylocations for said data. In network computer applications, a cachedevice or server may be provided to network users to supply lowerretrieval latencies, reduce service provider requests and provide otherimproved system efficiencies with respect to requests served by cachedata compared to requests that require service by other networkresources, for example by another service provider server or memorydevice in communication with the network.

BRIEF SUMMARY

According to one embodiment of the present invention, a method formanaging a cache includes providing a cache server that determines fromfirst metadata of a received first service request whether a dataresponse to a previously received second request and satisfying thefirst request may be cached in a cache managed by the cache server as afunction of recognizing a cacheable method name specification within themetadata by a service provider associated with the request. The methodfurther includes determining whether the first request is an inquiryrequest or an update request as a function of comparing an updatefrequency specification in the first request metadata to a value of atime parameter associated with the cacheable method name in themetadata, if determined that the first request may be satisfied by thedata response to the second request. The method also includes searchingthe cache for the data response to the second request if determined thatthe data response is a cacheable response and that the first request isthe inquiry request, and sending the request on to a service providerthrough a network communication for return of a service providerresponse if determined that the data response is not a cacheableresponse or that the first request is an update request.

In one aspect, an apparatus for managing a cache is provided thatincludes a network cache server to control a cache and that determinesfrom first metadata of a received first service request whether a dataresponse to a previously received second request and satisfying thefirst request may be cached in a cache managed by the cache server as afunction of recognizing a cacheable method name specification within themetadata by a service provider associated with the request. The cacheserver further determines whether the first request is an inquiryrequest or an update request as a function of comparing an updatefrequency specification in the first request metadata to a value of atime parameter associated with the cacheable method name in themetadata, if determined that the first request may be satisfied by thedata response to the second request. The cache server also searches thecache for the data response to the second request if determined that thedata response is a cacheable response and that the first request is theinquiry request, and sends the request on to a service provider througha network communication for return of a service provider response ifdetermined that the data response is not a cacheable response or thatthe first request is an update request.

In one aspect, a computer program product for managing a cache isprovided that includes program instructions stored on a computerreadable storage medium. First stored program instructions are tocontrol a cache by determining from first metadata of a received firstservice request whether a data response to a previously received secondrequest and satisfying the first request may be cached as a function ofrecognizing a cacheable method name specification within the metadata bya service provider associated with the request. Second stored programinstructions are to determine whether the first request is an inquiryrequest or an update request as a function of comparing an updatefrequency specification in the first request metadata to a value of atime parameter associated with the cacheable method name in themetadata, if determined that the first request may be satisfied by thedata response to the second request. Third stored program instructionsare to search the cache for the data response to the second request ifdetermined that the data response is a cacheable response and that thefirst request is the inquiry request. Additionally, fourth storedprogram instructions are to send the request on to a service providerthrough a network communication for return of a service providerresponse if determined that the data response is not a cacheableresponse or that the first request is an update request, or noappropriate data found and returned from the cache.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

These and other features of this invention will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings in which:

FIG. 1 is a flowchart illustrating an embodiment of a method or systemfor cache management according to the present invention.

FIG. 2 is a block diagram of an exemplary computerized implementation ofan embodiment of the present invention.

The drawings are not necessarily to scale. The drawings are merelyschematic representations, not intended to portray specific parametersof the invention. The drawings are intended to depict only typicalembodiments of the invention and, therefore, should not be considered aslimiting the scope of the invention. In the drawings, like numberingrepresents like elements.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

A cache may receive multiple data requests from one client or frommultiple clients, for example through a web service, and wherein anappropriate response to each of the requests is the same and may befound to reside on the cache. However, differences in coding and/ormetadata associated with each of the multiple identical requests maymake it difficult to recognize that each request may be satisfied by thesame cached data, and this may result in unnecessary forwarding of someof the requests to another network resource or service for return ofdata and return of the same to the requesting client. Further, absentdeveloping a distinguishing elaborate logic prior art web services cachemanagement may be unable to distinguish between requests that may beserved by cache data (which may be referred to as an inquiry request),and requests that cannot but instead require updated data to berequested and returned from another resource (which may be referred toas an update request), and thus they may inappropriately return aresponse from the cache to an update request.

Some resources or services may charge based on an amount of requestsserviced, or limit the amount of requests that may be serviced.Forwarding requests for processing and return of data by other serviceproviders or by main memory resources also imposes higher bandwidthcosts and latencies relative to serving a request from cache. Thus, itis desirable to prevent the unnecessary forwarding of requests forprocessing and return of data by other service providers or resourceswhich may instead by served by a response already saved in the cache.

Metadata is generally known as data that describes attributes of otherdata, and may be understood to connote data within a request item thatprovides information about the request item itself, for example a titlestring within a media file or device settings used in the creation of animage file embedded in the image file. In a web services context, eachrequest generally contains code and other data that may also includemetadata, or that may be used to generate metadata useful in processingthe request and determining whether it may be satisfied by data alreadywithin a cache and associated with an earlier similar or identicalrequest.

Problems arise in matching requests to other requests and thereby to thesame cached data that may satisfy each request, due to variableinformation within each request that is unique to each request orresponse and which may be used as or to generate metadata about therequest useful in processing the request. Illustrative but notexhaustive examples of request variable information include transactionIDs and time stamps, and other examples will be apparent to one skilledin the art.

Hash value metadata may be generated from the code and parameters of arequest and used to process a request by a cache server. In one example,a first inquiry to an account information inquiry service utilizing acache server has a first hash value derived from the code and parametersof the request which include an account number and also a time of therequest. A cache server may be configured to search the cache for dataresponsive to the first request stored in the cache by using the firstrequest hash value as a key; if not found, the first request is sent toa service provider and response data from the service provider is storedin the cache using the first request hash value as the key. A secondinquiry received subsequent to the first for the same account may beserved by the data cached in response to the first request. However, byusing hash value metadata of the second request, the cache server failsto recognize that the cached data may satisfy the second request: thesecond request has a second hash value that is different from the firstrequest hash value as it is derived from the same account number valuebut also from a different variable information, here a later time valueof the second request. Thus, using the second hash value as a key, thecache server will not find the response data from the service providerstored in the cache in response to the first request, as it is storedusing the different first request hash value, and the cache server willinstead forward the second request to the service provider, and the samedata will be returned, and again stored in the cache now using thesecond, different hash value. Thus, searching the cache as a function ofa hash key of request data is not effective, since an exact match ofeach request data is required, and this will not be achieved due todifferences in the variable information unique to each of the first andsecond requests.

It may also be possible to identify data appropriately cached andreturned to each of identical requests by determining whether a requestis an inquiry request or an update request. In general, an inquiryrequest is one that may be satisfied by the same, unchanging data valuefor each of a plurality of requests, for example an account value at aspecific time and/or date. An update request is one that requires acurrent or new value different from that cached in response to a priorrequest, for example for a time-limited offer or sale price quote for apublicly traded equity. If properly distinguished by a cache server, aninquiry request response may be returned from the cache and an updaterequest forwarded to another service or resource for return of anappropriate updated response.

Reading or otherwise analyzing the metadata of a request may enabledistinguishing inquiries from updates as a function of a name of anassociated cached service within the metadata. However, it may bedifficult to determine which services should be cached when they arecalled as a function of a service name as different service providers orweb services interfaces may utilize a great variety of different namingconventions. For example, a service provider or web services interfacemay utilize “inquire” as an inquiry method name rather than an expected,recognized “getXxxx,” or “update” rather than an expected, recognizedupdate method name “setXxxx.” Determinations may also fail where inquirymethods and update methods are not provided at an expected proportion ofone-to-one, for example using only one inquiry method name (e.g.“getAll”) while using two different update method names (e.g. “setA” and“setB”) may result in failure to recognize one of the update methodnames. A method may also be effectively misnamed; for example, a methodnamed “inquire” may appear through analysis of its metadata name to bean inquiry, but the method may actually include an update method, forexample recording an internal log in a database as may be common withfinancial systems services methods. Additionally, functions with thesame name may behave differently depending not upon a method name butupon an associated parameter value; for example, an inquiry method maybe named “exec(“A”)” while an associated update method is named“exec(“B”),” and hence they are distinguishable only by the parametervalue. Thus, method name analysis may not adequately determine whichservices should be cached when they are called.

Referring now to FIG. 1, an embodiment of a method or system for cachemanagement according to the present invention is illustrated, wherein aweb services cache server receives a web service request and determinesfrom metadata of the request whether a data response satisfying therequest may be already cached as a function of a method namespecification by a service provider associated with the request. Thedetermination may also be based on a return value specification, aparameter associated with the method name and/or an update frequencyspecification by the service provider. Examples of said determinationsmay include “Is the response data for this method name cacheable?”and/or “Does an appropriate update frequency for the return value orother parameter indicate an update is required even if cacheable?”

In one embodiment of a process/system of FIG. 1, a web services cacheserver receives a web service request at 101 and at 103 determineswhether a data response satisfying the request may be already cached asa function of determining a method name specification by a serviceprovider associated with the request within the metadata of the request.The determination may also be based on other metadata associated withthe specified method name within the metadata. Illustrative but notexhaustive examples include a return value specification, a parameterassociated with the method name and/or an update frequency specificationby the service provider.

If an appropriate response to the request is not a cacheable response,then at 105 the cache server sends the request on to a service providerfor return of an appropriate response. Alternatively, if an appropriateresponse to the request is a cacheable response, then at 107 the cacheserver further construes the metadata to determine whether the requestis an inquiry or an update request. If the request is determined to bean update request at 107, then the request is instead sent on to theservice provider at 105. If instead the request is determined to be aninquiry request at 107, then the cache server looks for an appropriateresponse already stored in the cache at 111 and either returns a foundresult to the requester at 113 and ends the process at 115, or sends therequest on to the service provider at 105 if no appropriate or otherwisematching response is found in the cache.

Though the present embodiment utilizes a two-part process (103 and 107),it will be understood that other embodiments may combine the inquiryinto a single inquiry, or perform the 103 and 107 inquiries in adifferent order, and alternative ones of the 103 and 107 inquiries mayserve as a condition predicate for the other in determining whether theresponse may be cached, and the present embodiment is not to beconstrued to limit the invention(s) claimed to the examples herein.

A response returned by the service provider in response to theforwarding of the request at 105 is received at 117, wherein itsmetadata is construed to determine if the response is itself cacheable(for example, “will it satisfy a subsequent inquiry within an updatefrequency?” and/or reapplying either or both of the inquiries of 103 and107). Thus, the service provider response is cached if cacheable at 119,and not cached if not cacheable at 121, and the response returned to therequester at 113. With return of an appropriate response to therequestor, the process ends at 115.

Cacheable properties and update frequencies useful in at least one ofthe determinations of the process at 103, 107 and 117 may be determinedfrom request metadata and/or directly expressed or specified in thesource code, parameters or within the metadata comments of the requestin a service interface, or in an Integrated Development Environment(IDE) by each service.

A service interface provides an entry point used to access afunctionality exposed by a service provider software application capableof being accessed by a user over the internet or other communicationnetwork. Generally, a service interface is designed to decouplecommunication methods from the application's business logic system,thereby enabling communication with a variety of different network usersin a method or protocol that may be simpler (or at least different) thanthe underlying system semantics and application logic. The serviceinterface may provide a barrier that enables application logic to changewithout affecting users of the interface, encapsulate aspects of anetwork protocol used for communication between the requesting user andthe underlying service, translate between user/requester data formatsand the data formats that the service expects, and provide still otherdata handling functions.

Comments within the request may also be construed, for example commentswithin the Web Service Description Language (WSDL) of the request. WSDLis an Extensible Mark-up Language (XML) language that containsinformation about an interface, semantics and other administrativeinformation for a call to a web service pursuant to a set of rules forencoding documents electronically. Information in a WSDL file may beused to form a Simple Object Access Protocol (SOAP) request to the cacheserver or other network computer. In some embodiments of the presentinvention, determination of the metadata in at least one of theprocesses at 103, 107, 109 and 117 include application of a staticanalysis tool to the metadata source code in the data request receivedat 101, the web services cache server thereby construing the metadataand responsively performs the detailed cache control illustrated inFIG. 1. Table 1 provides one example of a set of WSDL definitions thatmay be used in the source code of the 101 request for data analysis by astatic analysis tool.

TABLE 1 <wsdl:definitions ..> <wsdl:types> ... </wsdl:types><wsdl:message ...> ... </wsdl:message> <wsdl portType ...><wsdl:operation ...> </wsdl:operation> </wsdl:portType> <wsdl:binding>... </wsdl:binding> <wsdl:service> ... </wsdl:service></wsdl:definitions>

Table 2 provides an example of a set of inquiry commands that may beused in the request received at 101 for retrieving information from theservice provider at 105 with regard to an account:

TABLE 2 int withdraw(String num, int amount); int inquireAccount(Stringnum); int inquireInterest( ); int inquireInterest(Calendar c);

Table 3 is an example of a determination of the request metadata, and/ora specification within the metadata by a service provider of cacheableand update properties of a data request useful in at least one of thedeterminations of the process at 103, 107, 109 and 117:

TABLE 3 <webServiceCache> <operation name=“inquireInterest”return=“int”> </operation > <operation name=“inquireInterest”return=“int” > <parm type=”Calendar”/> </operation.> <webServiceCache>

Thus, in one embodiment of the process/system of FIG. 1, the serviceprovider associated with the request has defined the “inquireInterest”command for return of “int” as a cacheable method name in the metadataof the request, and further indicated the parameter value “Calendar” asan update frequency of the data for determination at 103 and/or 117 asto whether the response is cacheable, and/or is in fact cached. Analysisof the value of the calendar parameter (“Calendar”) at 107 may includecomparison of the value to an update frequency specified by the serviceprovider, and may be used to determine if the request is an inquiry thatmay be served by a cache value or an update; for example, if the requestis aged out over any possible stored value, then it is forwarded as anupdate, wherein if not aged-out, it is an inquiry that may be satisfiedby the cache. Analysis of the value of the calendar parameter at 111 mayalso indicate whether a match may be returned from the cache: is a matchfound in the cache aged out or otherwise too old to satisfy the request,and if so then treat as an update and forward to the service provider at105 instead of returning the aged-out found value.

The calendar parameter or other parameter value may also be recognizedor determined in a qualifying process in at least one of the cacheabledeterminations of the process at 103 and 117. For example, analysis of atime or duration parameter value of the request at 103 and/or 107 maydetermine that the request must be serviced from the service provider at105 rather than the cache, independent of any inquiry or updateclassification determination. Further, it will also be understood thatin alternative embodiments a method name specification within themetadata by the service provider may be sufficient to identify therequest as an inquiry or an update without further recognition ordetermination of either of a return value or an update frequencyspecification associated with said method name definition.

Cache control and management is thus driven by request or responsemetadata and performed in response to service provider specifications orparameter values, wherein policies or rules are specified or used on theservice provider side rather than the client or cache server side of thetransaction. Policy examples used at 103, 107 or 117 to determinewhether a response may be retrieved from cache, or to determine that aresponse returned from the service provider at 117 should be saved tocache, include a time interval period from a last request and an accessfrequency, and still others will be apparent to one skilled in the art.Rules may also be determined or specified to apply to parameters forcaching determinations at 103, 107 or 117; for example, caching may beindicated or performed when a return value or associated parameter is acertain specified or determined value.

In another aspect, metadata may be excluded in caching searching orcaching decisions. In particular, some request variable information maybe excluded from caching storage and search methods and systems in orderto enable retrieval of cache data to satisfy subsequent requests withdifferent variable information values. For example, the requesttransaction IDs or time stamps that are problematic is hash-basedmatching as discussed above, may be excluded from hash keydeterminations, enabling other requests with specified method names tobe served by the same cache data, and other excludable parameters mayalso be recognized as useful in excluding for cache management accordingto the present invention.

Metadata cache commands, for example those illustrated in Table 3, maybe generated as an extension of a web service wizard or other userinterface by each service provider. In one embodiment, radio buttonfields may be provided within a user entry window next to each of aplurality of service provider command definitions wherein a serviceprovider side user of the interface may indicate whether each command iscacheable or not by selecting or not selecting each of said radiobuttons. In another embodiment, metadata generation may be an extensionof a WSDL editor, for example through toggling of respective radiobutton fields associated with each command definition on the serviceprovider side. Cache information may also be incorporated in WSDLcomments, the comments construed and used to generate the cache metadatafor use in the determination at 101.

In one aspect of the present invention, cache metadata is distributed ona cache server on which an entity controlling the cache is running. Inthe case of an embodiment in which metadata is generated in thetransaction or management thereof, a metadata repository is prepared andutilized in the cache management, for example at 103, 107, 109 and 117in FIG. 1. In the case of an embodiment in which WSDL comments are used,said metadata is already incorporated in the WSDL and a metadatarepository is not required.

Prior art cache management methods include methods for implementingcache by using custom code (for example, Java) to build cacheidentifications (ID's) from input SOAP message content throughcalculating a hash of a SOAP envelope and using SOAP header entries andoperation and part parameters. However, service provider and webservices client cache may be run by different operators, and in thissituation caching to handle the parameters of a web service provider canbe realized only if the cache operator can effectively estimate theintentions of the provider, internal processing from WSDL and/or webservices functions from the service provider WSDL. The cache operatormust also code the caching function(s) as a function of saidestimation(s), configure an appropriate cache XML and then deploy it.Problems may arise in adequately performing said estimations as neithercache operation policies nor internal processing is generally expressedin the service provider WSDL. Further, the cache operator must alsodesign, implement, and manage codes for each service to be cached. Ifthe internal processing of any of the various service providers isunknown to the cache operator, it may not be possible to determinewhether caching decisions are performed appropriately for eachrespective service. The cache operator must also decide a number ofpolicies (for example, a cache-invalidation scheme) and appropriateconfigurations cannot be performed unless implementation and operationof the service provider are clear to the cache provider.

Accordingly, prior art cache management relying upon custom code writtenand implemented by the client cache by estimating on the cache serverside internal processing of the service provider based on the externalspecification (WSDL) of the service provider, update frequencies, dateand time and other un-cacheable parameter and value indicators maysuffer from inappropriate estimations as to the service providersettings, which may render initial cache management implementation andconfiguration deficient. Further, it may not be possible for a cacheoperator to correct said deficiencies even if recognized as theintentions or internal processing of the service provider side cannot becorrectly reflected.

In contrast, embodiments of the present invention enable the serviceprovider to unambiguously specify which inquiry services are cacheable,and each service provider may provide different specifications as towhen any of their cacheable services are to be updated (once a day,every five minutes, etc.) rather than returned from cache, eliminatingguesswork and estimations on the cache server side. Custom WSDL code andpolicies reflecting intentions of the provider and internalimplementation can be correctly configured on the cache server, so thatstatic analysis tools or other functions according to the presentinvention may automatically generate custom WSDL code using web servicesclient cache functions realized from the request metadata. Embodimentsof the present invention enable the provider side to configure cacheoperation policies and parameter handling methods at the time of designand implementation of each web service, allowing the cache operator sideto realize automatic generation of cache policy configurations andparameter handling methods in accordance with the provider's intentionsbased on WSDL or information in a metadata repository and to apply themon the cache server.

Referring now to FIG. 2, an exemplary computerized implementation of anembodiment of the present invention includes a cache server 304 incommunication with one or more client devices 336 that request data thatmay reside in a cache 332 managed by the cache server 304 or that mayneed to be sent on for service by a service provider 328 incommunication with the cache server 304 through a computer networkinfrastructure 308. The implementation is intended to demonstrate, amongother things, that the present invention could be implemented within anetwork environment (e.g., the Internet, a wide area network (WAN), alocal area network (LAN) or a virtual private network (VPN), etc.)Communication throughout the network 308 can occur via any combinationof various types of communications links; for example, communicationlinks can comprise addressable connections that may utilize anycombination of wired and/or wireless transmission methods.

Where communications occur via the Internet, connectivity could beprovided by conventional TCP/IP sockets-based protocol, and an Internetservice provider could be used to establish connectivity to theInternet. Still yet, the network infrastructure 308 is intended todemonstrate that the file download application can be deployed, managed,serviced, etc. by a service provider who offers to implement, deploy,and/or perform the functions of the present invention for others.

The cache server 304 comprises various components, some of which areillustrated in FIG. 2, though it is to be understood that the cacheserver 304 may comprise more components. More particularly, as shown,the cache server 304 includes a processing unit (CPU) 312 incommunication with one or more external I/O devices/resources 328 andcache storage systems 332. In general, the processing unit 312 executescomputer program code, for example the code stored on a computerreadable storage medium 316, that causes the cache server 304 toimplement a static analysis tool 202 that determines the metadata in atleast one of the processes at 103, 107, 109 and 117 in FIG. 1.

The network infrastructure 308 is only illustrative of various types ofcomputer infrastructures for implementing the invention. For example, inone embodiment, computer infrastructure 308 comprises two or morecomputing devices (e.g., a server cluster) that communicate over anetwork. Moreover, the cache server 304 is only representative ofvarious possible computer systems that can include numerous combinationsof hardware. To this extent, in other embodiments, the cache server 304can comprise any specific purpose computing article of manufacturecomprising hardware and/or computer program code for performing specificfunctions, any computing article of manufacture that comprises acombination of specific purpose and general purpose hardware/software,or the like. In each case, the program code and hardware can be createdusing standard programming and engineering techniques, respectively.

Moreover, the processing unit 312 may comprise a single processing unit,or be distributed across one or more processing units in one or morelocations, e.g., on a client and server. Similarly, the memory 316and/or the cache system 332 can comprise any combination of varioustypes of data storage and/or transmission media that reside at one ormore physical locations. Further, I/O interfaces 328 can comprise anysystem for exchanging information with one or more of the serviceprovider 328 and client(s) 336. Still further, it is understood that oneor more additional components (e.g., system software, math co-processingunit, etc.) not shown in FIG. 2 can be included in a computer that maybe represented by 304, 328 or 336.

In another embodiment, the invention provides a method that performs theprocess steps of the invention on a subscription, advertising and/or feebasis. That is, a service provider could offer to manage the cache 332as a function of request metadata as described herein. In this case, theservice provider can create, maintain, and support, etc., a computerinfrastructure, such as the network computer infrastructure 308 thatperforms the process steps of the invention for one or more customers.In return, the service provider can receive payment from the customer(s)under a subscription and/or fee agreement and/or the service providercan receive payment from the sale of advertising content to one or morethird parties.

In still another embodiment, the invention provides acomputer-implemented method for executing one or more of the filedownloading processes, systems and articles described above. In thiscase, a computer infrastructure, such as the computer infrastructure308, can be provided and one or more systems for performing the processsteps of the invention can be obtained (e.g., created, purchased, used,modified, etc.) and deployed to the computer infrastructure. To thisextent, the deployment of a system can comprise one or more of: (1)installing program code on a computing device, such as the cache server304, from a computer-readable medium; (2) adding one or more computingdevices to the computer infrastructure; and (3) incorporating and/ormodifying one or more existing systems of the computer infrastructure toenable the computer infrastructure to perform the process steps of theinvention.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising” when used in this specification, specify thepresence of stated features, integers, steps, operations, elementsand/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. As used herein, it is understood thatthe terms “program code” and “computer program code” are synonymous andmean any expression, in any language, code or notation, of a set ofinstructions intended to cause a computing device having an informationprocessing capability to perform a particular function either directlyor after either or both of the following: (a) conversion to anotherlanguage, code or notation; and/or (b) reproduction in a differentmaterial form. To this extent, program code can be embodied as one ormore of: an application/software program, component software/a libraryof functions, an operating system, a basic I/O system/driver for aparticular computing and/or I/O device, and the like.

Certain examples and elements described in the present specification,including in the claims and as illustrated in the Figures, may bedistinguished or otherwise identified from others by unique adjectives(e.g. a “first” element distinguished from another “second” or “third”of a plurality of elements, a “primary” distinguished from a “secondary”one or “another” item, etc.) Such identifying adjectives are generallyused to reduce confusion or uncertainty, and are not to be construed tolimit the claims to any specific illustrated element or embodiment, orto imply any precedence, ordering or ranking of any claim elements,limitations or process steps.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present invention has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the invention in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the invention. Theembodiment was chosen and described in order to best explain theprinciples of the invention and the practical application, and to enableothers of ordinary skill in the art to understand the invention forvarious embodiments with various modifications as are suited to theparticular use contemplated.

1. A method for managing a cache, comprising: providing a cache serverprocessing unit that determines from metadata of a received firstservice request whether a data response to a previously received secondrequest and satisfying the first request may be cached in a cachemanaged by the cache server by determining if an operation name of acommand within the received first request is defined in combination witha return data identification as a cacheable method name specificationwithin the first request metadata; if determined that the commandoperation name is defined in combination with the return dataidentification within the received first request metadata as thecacheable method name specification, determining that the first requestis an inquiry request that may be satisfied by a data value from thepreviously received second request if a value of a time parameterassociated with the cacheable method name in the metadata is not agedout by an update frequency specification defined in the first requestmetadata; searching the cache for the data response to the secondrequest in satisfaction of the received first service request ifdetermined that the command operation name is defined in combinationwith the return data identification within the received first requestmetadata as the cacheable method name specification, and that the firstrequest is the inquiry request; and sending the request on to a serviceprovider through a network communication for return of a serviceprovider response if determined that the command operation name is notdefined in combination with the return data identification within thereceived first request metadata as the cacheable method namespecification, or that the first request is not the inquiry request. 2.The method of claim 1, the searching the cache for the data responsefurther comprising: utilizing the first request metadata to search thecache by excluding variable transaction identification metadata of thefirst request metadata that is different from variable transactionidentification metadata of the second request; and returning the cacheddata response to the second request.
 3. The method of claim 2, whereinthe received first request metadata comprises web service descriptionlanguage; and wherein the cache server processing unit determines if thecommand operation name is defined in combination with the return dataidentification within the received first request metadata as thecacheable method name specification by construing the Web ServiceDescription Language metadata via application of a static analysis tool.4. The method of claim 3, further comprising: determining if the serviceprovider response returned from the service provider is cacheable as afunction of comparing an update frequency specification to a value of atime parameter of the service provider in metadata of the serviceprovider response; caching the service provider response if determinedthat the service provider response is cacheable and forwarding theservice provider response to a first requestor in response to the firstrequest; and forwarding the service provider response to the firstrequester without caching the service provider response if determinedthat the service provider response is not cacheable.
 5. The method ofclaim 3 wherein the update frequency is specified by the serviceprovider in a service interface through at least one of a source code, aparameter value and a comment within the web service descriptionlanguage of the first request.
 6. The method of claim 5, wherein theservice interface comprises a service provider software application toreceive the first request and return the service provider response usinga business logic system having a protocol different from a protocol ofan underlying system application logic of the cache server.
 7. Themethod of claim 5, further comprising determining as a function ofconstruing the comment at least one of whether the data responsesatisfying the request may be cached in the cache, whether the firstrequest is the inquiry request, and whether the service providerresponse returned by the service provider is cacheable.
 8. The method ofclaim 5, wherein the update frequency specification is a time intervalperiod policy or an access frequency policy.
 9. The method of claim 5,further comprising: generating the first request metadata in response toreceiving the first request; and preparing and utilizing a metadatarepository to handle the generated first request metadata.
 10. Apparatusfor managing a cache, comprising: a network cache server comprising aprocessing unit in communication with a computer readable memory and atangible computer-readable storage medium; wherein the processing unit,when executing program instructions stored on the tangiblecomputer-readable storage medium via the computer readable memory:determines from first metadata of a received first service requestwhether a data response to a previously received second request andsatisfying the first request may be cached in a cache managed by thecache server by determining if an operation name of a command within thereceived first request is defined in combination with a return dataidentification as a cacheable method name specification within the firstrequest metadata; if the command operation name is determined as definedin combination with the return data identification within the receivedfirst request metadata as the cacheable method name specification,determines that the first request is an inquiry request that may besatisfied by a data value from the previously received second request ifa value of a time parameter associated with the cacheable method name inthe metadata is not aged out by an update frequency specificationdefined in the first request metadata; searches the cache for the dataresponse to the second request in satisfaction of the received firstservice request if determined that the command operation name is definedin combination with the return data identification within the receivedfirst request metadata as the cacheable method name specification, andthat the first request is the inquiry request; and sends the request onto a service provider through a network communication for return of aservice provider response if determined that the command operation nameis not defined in combination with the return data identification withinthe received first request metadata as the cacheable method namespecification, or that the first request is not the inquiry request. 11.The apparatus of claim 10, wherein the processing unit, when executingthe program instructions stored on the computer-readable storage mediumvia the computer readable memory, further searches the cache for thedata response by utilizing the first request metadata to search thecache and return the cached data response to the second request byexcluding variable transaction identification metadata of the firstrequest metadata that is different from variable transactionidentification metadata of the second request.
 12. The apparatus ofclaim 11, wherein the received first request metadata comprises webservice description language; and wherein the processing unit, whenexecuting the program instructions stored on the computer-readablestorage medium via the computer readable memory, determines if thecommand operation name is defined in combination with the return dataidentification within the received first request metadata as thecacheable method name specification by construing the web servicedescription language metadata via application of a static analysis tool.13. The apparatus of claim 11, wherein the processing unit, whenexecuting the program instructions stored on the computer-readablestorage medium via the computer readable memory, further: determines ifthe service provider response returned from the service provider iscacheable as a function of comparing an update frequency specificationto a value of a time parameter of the service provider in metadata ofthe service provider response; caches the service provider response ifdetermined that the service provider response is cacheable and forwardthe service provider response to a first requestor in response to thefirst request; and forwards the service provider response to the firstrequester without caching the service provider response if determinedthat the service provider response is not cacheable.
 14. The apparatusof claim 11, wherein the update frequency is specified by the serviceprovider in a service interface through at least one of a source code, aparameter value and a comment within the web service descriptionlanguage of the first request; and wherein the service interfacecomprises a service provider software application to receive the firstrequest and return the service provider response using a business logicsystem having a protocol different from a protocol of an underlyingsystem application logic of the cache server.
 15. A computer programproduct for managing a cache, the computer program product comprising: acomputer readable storage medium; first program instructions to controla cache by determining from first metadata of a received first servicerequest whether a data response to a previously received second requestand satisfying the first request may be cached by determining if anoperation name of a command within the received first request is definedin combination with a return data identification as a cacheable methodname specification within the first request metadata; second programinstructions to, if the command operation name is determined as definedin combination with the return data identification within the receivedfirst request metadata as the cacheable method name specification,determine that the first request is an inquiry request that may besatisfied by a data value from the previously received second request ifa value of a time parameter associated with the cacheable method name inthe metadata is not aged out by an update frequency specificationdefined in the first request metadata; third program instructions tosearch the cache for the data response to the second request insatisfaction of the received first service request if determined thatthe command operation name is defined in combination with the returndata identification within the received first request metadata as thecacheable method name specification, and that the first request is theinquiry request; and fourth program instructions to send the request onto a service provider through a network communication for return of aservice provider response if determined that the command operation nameis not defined in combination with the return data identification withinthe received first request metadata as the cacheable method namespecification, or that the first request is not the inquiry request; andwherein the first, second, third and fourth program instructions arestored on the computer readable storage medium.
 16. The computer programproduct of claim 15, further comprising: fifth program instructionsstored on the computer readable storage medium to search the cache forthe data response by utilizing the first request metadata to search thecache and return the cached data response to the second request byexcluding variable transaction identification metadata of the firstrequest metadata that is different from variable transactionidentification metadata of the second request.
 17. The computer programproduct of claim 16, wherein the received first request metadatacomprises web service description language; and wherein the firstprogram instructions are further to determine if the command operationname is defined in combination with the return data identificationwithin the received first request metadata as the cacheable method namespecification by construing the web service description languagemetadata via application of a static analysis tool.
 18. The computerprogram product of claim 16, further comprising: ninth programinstructions stored on the computer readable storage medium to determineif the service provider response returned from the service provider iscacheable as a function of comparing an update frequency specificationto a value of a time parameter of the service provider in metadata ofthe service provider response; tenth program instructions stored on thecomputer readable storage medium to cache the service provider responseif determined that the service provider response is cacheable andforward the service provider response to a first requestor in responseto the first request; and eleventh program instructions stored on thecomputer readable storage medium to forward the service providerresponse to the first requester without caching the service providerresponse if determined that the service provider response is notcacheable.
 19. The computer program product of claim 16, wherein theupdate frequency is specified by the service provider in a serviceinterface through at least one of a source code, a parameter value and acomment within the web service description language of the firstrequest; and wherein the service interface comprises a service providersoftware application to receive the first request and return the serviceprovider response using a business logic system having a protocoldifferent from a protocol of an underlying system application logic ofthe cache server.
 20. The computer program product of claim 16, furthercomprising: twelfth program instructions stored on the computer readablestorage medium to generate the first request metadata; and thirteenthprogram instructions stored on the computer readable storage medium toprepare and utilize a metadata repository for handling the generatedfirst request metadata.